The present invention relates generally to roof structures, and more particularly to the fabrication of panelized roof structures.
Roofs for contemporary buildings, particularly light industrial buildings having rectangular-shaped roofing, typically are formed from roof panel structures that are attached to main supporting beams. In general, a roof panel structure includes a purlin (i.e., a major beam) that, when installed, is attached orthogonally to the main supporting beams of the structure, subpurlins (i.e., minor beams such as lumber stiffeners) that are attached orthogonally to the purlin, and diaphragms (e.g., wood structural panels) that are nailed to the subpurlins and the purlin for structural and shear support. Completed roof panel structures may be 25 to 80 feet in length or even longer, and are often lifted to and placed on the main supporting beams by a crane or forklift. Once in place, the roof panel structures are typically nailed to the main supporting beams and adjacent roof panel structures.
In practice, each of the components of the roof panel structures is brought to a site and the roof panel structures are assembled by hand. Some manufacturers preassemble the subpurlins and the diaphragms offsite (typically in four-foot segments, but sometimes in eight-foot segments), and use the preassembled subpurlins and diaphragms at the site to form the roof panel structures. Even if the preassemblies are used, however, many carpenters and other construction workers are required in the roofing area to complete assembly and/or installation of the roof panel structures. Thus, although present roof panel structures work well for their intended purpose, their assembly can be time consuming and expensive. Moreover, the amount of labor involved may introduce errors into assembly, which may cause additional expenses of time, labor, and materials. In addition, the labor involved may be somewhat dangerous and/or strenuous, and very often requires young, attentive workers.
The present invention provides a portable roof panel structure assembly mechanism that may be transported to a construction site and that is used to automatically assemble roof panel structures at the site. The roof panel structure assembly mechanism includes a purlin feeder, subpurlin clamping mechanisms and feeders, and a diaphragm feeder. The purlin feeder advances a purlin into an assembly station. The subpurlin feeders insert a subpurlin into each of a plurality of subpurlin clamping mechanisms, and the clamping mechanisms advance into the assembly station and hold the subpurlins against the section of the purlin that has been already advanced into the assembly station. The diaphragm feeder places a diaphragm onto the subpurlins and the purlin at the assembly station. The components are then ready for attachment.
In accordance with one aspect of the present invention, one or more automatic nailers (e.g., nailing guns) may be used to attach the diaphragm, the subpurlins, and the purlin at the assembly station. The automatic nailers may be provided, for example, on a nailing carriage that moves with a lifting carriage that is used to deliver and place the diaphragm over the subpurlin and the purlin. If multiple nailing guns are used, particular guns may be fired according to the position of the gun and the length and/or width of the diaphragm. In accordance with an aspect of the present invention, once the subpurlins, purlin, and diaphragm are in place, the nailing of the components together occurs automatically.
In accordance with another aspect of the present invention, the purlin feeder includes a height adjustment mechanism that permits the top level of a purlin on the feeder to be adjusted to a preselected height, regardless of the height of the purlin. After the purlin has been raised or lowered to the preselected height, the purlin is advanced into the assembly station. Subpurlins and a diaphragm are moved against the purlin in the assembly station, and are attached to the purlin, such as by the automatic nailers on the nailing carriage. The purlin is then indexed the width of the diaphragm, and the next subpurlins and diaphragm are placed against the new section of the purlin, and may be attached to the purlin at the assembly station (e.g., by the nailing carriage).
The end of the purlin having subpurlins and diaphragm(s) attached thereto advances into an exit station. The exit station includes a support for the purlin, which is adjustable for height similar to, or the same as, the lifting mechanism for the purlin feeder. A second support is provided for the side of the assembled roof panel structure having the subpurlins and diaphragms (i.e., opposite the purlin). In accordance with another aspect of the present invention, a fork lift is provided with tines that are specially configured to lift the roof panel structure from the exit station.
In accordance with still another aspect of the present invention, the subpurlin clamping mechanisms are mounted on a carriage that advances the clamping mechanisms and the subpurlins into the assembly station. The carriage may, for example, include a clamping mechanism for each subpurlin. Feeders are provided to supply subpurlins to the clamping mechanisms. According to one aspect of the present invention, a separate subpurlin feeder is provided for each subpurlin clamping mechanism. The subpurlin feeders may be, for example, vertical magazines or indexing units that drop a bottom subpurlin into a subpurlin clamping mechanism while a penultimate subpurlin is supported.
The subpurlin clamping mechanisms may include clamps or pinchers that close on opposite sides of the subpurlin and thereby position a subpurlin in a subpurlin clamping mechanism. The clamps may include sensors for determining or confirming the thickness of a subpurlin in a subpurlin clamping mechanism.
A rod or other device may be used to press a subpurlin against the purlin after the carriage has advanced the subpurlins into the assembly station. A sensor may be used to determine the length of the stroke of the rod so that the subpurlin length may be detected or confirmed.
If the subpurlin includes brackets that are configured to extend over the purlin, in accordance with an aspect of the present invention, the carriage, the subpurlins, or the clamping mechanisms may be lifted as the brackets and subpurlins approach the purlin, so that the brackets are raised above a top edge of the purlin. This feature assures that the brackets clear the top edge of the purlin, instead of hitting the purlin as the brackets are advanced. The subpurlins, clamping mechanisms, or carriage may then be lowered, so that the brackets rest on top of the purlin.
In accordance with one aspect of the present invention, the diaphragm feeder includes a diaphragm carriage. In one embodiment, the diaphragm carriage includes the nailing carriage and a lifting carriage for lifting and placing the diaphragm onto the subpurlin and/or purlin. This lifting carriage may include some form of device for grasping a diaphragm, for example, suction cups.
The lifting carriage may lift the diaphragm from a pile of diaphragms. In accordance with another aspect of the present invention, the pile of diaphragms may be provided on a lift designed such that a top diaphragm stays at substantially the same height as diaphragms are removed.
In accordance with an aspect of the present invention, the lifting carriage is movable relative to the diaphragm carriage, and may, for example, be mounted on a diaphragm carriage for rotational and three dimensional movement. Sensors may be provided for aiding in proper alignment of a diaphragm held by the lifting carriage before the diaphragm is placed on the subpurlins and purlin.
The nailing carriage may be separate from the diaphragm carriage, or may be mounted thereon, for example, on a lower portion of the diaphragm carriage. In accordance with one aspect of the present invention, a diaphragm is lowered into place in the assembly station by the lifting carriage, and the automatic nailers nail the diaphragm to the purlin and/or subpurlin before the holding device releases the diaphragm. The holding mechanism is then released and the lifting carriage is retracted. The nailing carriage may then index so that the automatic nailers may nail the diaphragm at other locations. This process may be continued until nailing is complete. The nailing process may require turning some automatic nailers on in some locations, and off in others, depending upon the configuration of the roof panel structure and the location of the automatic nailers. To aid in aligning the automatic nailers in the proper location, the diaphragm carriage is configured to provide lateral movement of the nailing carriage, such as in the x- and y-directions.
The system may include a computer that permits the lengths and/or widths of the purlin, subpurlin, and diaphragms to be entered, so that the entire process is automatic once started. The sensors ensure that the appropriate size of subpurlins and diaphragms are in place and properly aligned, and serve as checks on the automated assembly.
The roof panel structure assembly mechanism of the present invention may be operated by a minimal number of workers, but yet generates multiple roof panel structures in a fraction of the time of conventional, manual assembly. In addition, workers that are less mobile, and that are not capable of strenuous activity may be used to operate the roof panel structure assembly mechanism. The roof panel structure assembly mechanism is fully portable, so it may be delivered to a site where assembly is needed.
Other advantages will become apparent from the following detailed description when taken in conjunction with the drawings, in which: